Red azo dye and process of making same.



UNITED STATES PATENT OFFICE.

oARL SCHIRMAOHER, OE SODEN, GERMANY, ASSIGNOR TO FARBWERKE,

voRM. MEISTER, LUOIUS & BRiiNING, OF HOOHST-ON-THE-MAIN, GER- MANY, A CORPORATION OF GERMANY.

RED AZO DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent N 0. 724,743, dated April 7, 1903.

Application filed February 4, 1903. Serial No. 141,849. (N specimens-l To all whom, it may concern:

Be it known that I, CARL SOHIRMAOHER, Ph. D., a citizen of the Empire of Germany, residing at Soden-on-the-Taunus, Germany,

have invented certain new and useful Improvements in the Manufacture of a Red Azo Dyestnfi, of which the following is specification.

I have found that by combining diazotized 1o para-nitranilinhomosulfonic acid with betanaphthol a red azo dyestuff may be obtained which is of great value for the manufacture of color-lakes. The hitherto unknown paranitranilinhomosulfonic acid may be obtained from ortho-chlorobenzylchlorid by first transforming the last-named compound with sulfite into ortho-chlorobenzylsulfonic acid, by then nitrating this acid in concentrated sulfuric acid to mononitrochlorobenzylsulfonic :0 acid, and by finally heating the latter with ammonia to 150 centigrade. The ammoniacal salt of para-nitranilinhomosulfonic acid is obtained as a yellow powder, readily soluble in hot Water.

2 5 To produce the azo dyestuff, I proceed, for instance, as follows: 24.9 parts, by weight, of nitranilinhomosulfonate of ammonia are dissolved in water, to which are added thirty parts of concentrated hydrochloric acid and 5c diazotized with a solution of seven parts of nitrite. The diazo solution is run into a solution of 14. 6 parts of beta-naphthol, ten parts of caustic-soda lye of Baum specific gravity, and twenty parts of sodium carbonate. After stirring for three hours the dyestufi is filtered. It is a red powder of bronze luster soluble with difliculty in cold water, pretty easily soluble in hot water with a yellow-red color. Concentrated sulfuric acid dissolves it with a blue-red color. The dyestuff is particularly suited for the manufacture of lakes.

Having now described my invention, what I claim is- 1 7 1. The herein-described process for the manufacture of a red azo dyestuff which consists, in combining the diazotized para-nitranilinhomosulfonic acid with beta-naphthol, substantially as set forth.

2. As a new product, the 2.20 dyestuff obtained by combining para-nitranilinhomosulfonic acid with beta-naphthol, being in form of its sodium salt a red powder of bronze luster; it is pretty easily soluble in hot water with a yellow-red color, but soluble with difficulty in cold water; concentrated sulfuric acid dissolves the dyestuff with a blue-red color.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

CARL SOHIRMACHER.

Witnesses:

ALFRED BRISBOIS,

J OHANN HARTENsTEIN. 

